For anything S&W revolver related, see Denny Reichard at Sand Burr Gun Ranch in Rochester. He is a revolver man through and through. He is known as one of the top revolver smiths in the country. He also teaches a good snubbie class. He is a crusty old retired cop, but is a wealth of information.
Sand Burr Gun Ranch
Wow...how did I not know about this place?! I have an old Dan Wesson .357 that I want to take apart this winter and give a good cleaning. Might be a good source for parts, etc., if I need anything. I got lucky last weekend and picked up a Ruger Security-Six .357...that is also one sweet gun!